Ruminations of Mysticism in Rabindranath Tagore and Rumi

That moves and That moves not; That is far and the same is near;That is within all this andThat also is outside all this.--- 5, Isha Upanishad

If ‘Duality’ is the nature of the entire universe, why do mystics aim at achieving non-duality through duality? Why do they introduce the concept of attaining the Supreme unionthrough constant practice of closeness to God? To answer these questions, we may have to turn to mystics who have recorded their lofty thoughts and pearls of wisdom in the literary pieces that have come down to us through generations.